Field devices are used as part of the automation of various industrial processes, for example for monitoring a production or manufacturing process or a processing process. The field devices may be the production plants themselves or devices for monitoring, preferably for controlling and/or regulating on the basis of detected field data, the industrial production means or plants used.
When operating the field devices in use, it is fundamentally possible to distinguish between two kinds of operation. First, the field devices can be actuated in situ by actuating the control elements provided. In this case, the operator needs to be with the field device or to travel to the plant in question. Secondly, remote operation of field devices from monitoring and maintenance centers is part of the known prior art.
Standard terminal programs used for operating the field devices in this context provide the operator with only very little convenience and generally permit only simple control actions. Particularly information in graphically processed form, for example measurement data, cannot be displayed to the operator.
Complex control programs have therefore been developed for remotely operating the field devices. Such complex control programs need to be installed on the respective field device and thus take up memory areas which are no longer available for the device application. In addition, every operator needs the control program required for the respective field device. In the case of field devices from different manufacturers or field devices from the same manufacturer with different releases, a large number of programs or program versions can become necessary relatively quickly.
Within the context of the remote operation and observation, it is firstly necessary to transfer data which need to be provided only once between the field devices and the apparatuses used by the operator. In addition, the field devices need to transfer electronic data to the apparatuses used by the operator which are no longer current after a short time and therefore need to be continually updated. These are, in particular, the measurement data detected in the field devices which need to be transmitted to the user apparatuses for evaluation and/or output.
In known control systems, the functions available to the operator are limited. Thus, in a network comprising a plurality of field devices and a plurality of apparatuses used by various operators for remote operation and observation, it is quite possible for a plurality of operators at one time to be using their control apparatuses to access just one and the same field device (cf. “Mini-Sternkoppler” [ministar coupler], Siemens AG, Order No. G34924-K2106-U1-A2, for example). It is an object of the invention to provide an improved way of operating and observing when remotely operating field devices, which is able to be used flexibly for various types of field device.